Fundus lesions in malignant hypertension. I. A pathologic study of experimental hypertensive choroidopathy.

Experimental hypertensive choroidopathy was studied in 29 eyes from 15 monkeys in which accelerated renovascular systemic hypertension developed after a modified Goldblatt procedure. We followed up the animals from five days to 21 months to examine clinically and histopathologically the spectrum of the pathologic process. The pathologic features of hypertensive choroidopathy in our animals may be categorized into three phases: (1) Acute ischemic phase: The initial change in the choroidal vasculature was constriction of arterioles, which leads to focal necrosis of the choriocapillaris and the retinal pigment epithelium and focal subretinal exudate. (2) Chronic occlusive phase: Occlusive changes involving arteries, arterioles, and choriocapillaris occurred later. (3) Chronic reparative phase: With time, recanalization took place at all levels of the choroidal vasculature. The subretinal fluid was reabsorbed, leaving diffuse patchy depigmentation of the retinal pigment epithelium, which followed lobular arrangement of the choriocapillaris. Arteriolization of the choriocapillaris developed; this seems to be a defense mechanism to withstand the elevated systemic blood pressure.